1. Field of the Invention
This invention relates to a switchgear cabinet monitoring arrangement with a control device for monitoring switchgear cabinet functions, including a door position, and for the generation of monitoring signals for signaling to and/or controlling components relating to the switchgear cabinet functions and installed in the switchgear cabinet or on the switchgear cabinet.
2. Description of Prior Art
A switchgear cabinet monitoring arrangement of this type is disclosed in German Patent Reference DE 196 09 689 A1. This known switchgear cabinet monitoring arrangement is matched to various uses of the switchgear cabinet and has versatile sensor devices for different measured values, such as temperature, closing status of the door, vibrations, smoke development and humidity, as well as with actuators, by which it is possible to react to sensor signals. With control and regulation options, there is a design of the switchgear cabinet for a multitude of uses, for which the control device with the signal processing and evaluation units is elaborately designed.
One object of this invention is to provide a switchgear cabinet monitoring arrangement, which requires little space, that can be simply assembled and can also retrofitted.
This object achieved with a switchgear monitoring arrangement as described in this specification and in the claims. A control device is limited to monitoring preselectable threshold values. A door position switch is installed on the device housing or installed in it, and the device housing has one or several indicator elements which react with a visual or acoustic indication when at least one threshold value is upwardly or downwardly exceeded.
With the limitation of the control device to monitoring preselectable threshold values and to the corresponding indicator elements, as well as the arrangement of a door position switch on the device housing, it is possible to keep the switchgear cabinet monitoring arrangement comparatively small and simple in construction. It therefore requires little space and can easily be housed without problems in the switchgear cabinet, even at a later time. The door position switch can be actuated directly with the door or indirectly with intermediate elements. Through the monitoring signals it is possible to control, or respectively regulate, suitable units installed in or on the switchgear cabinet via a more elaborate further control device arranged outside of the device housing.
An advantageous structure results because the door position switch installed in the device housing projects beyond an associated housing wall with only a slideable or pivotal switch element. Thus the door position switch is housed in a protected manner, and its connecting contacts for receiving the monitoring signals are placed into the interior of the device housing.
The steps, wherein the door position switch is housed in one housing section and the control device in a further housing section placed on top of the first, contribute to a simple, well arranged structure. A separation essentially into an electrical section with the control device and an indicator, and a mechanical section with the installed door position switch, thus results. In this case the electrical section can be maintained, or respectively exchanged, essentially independently of the mechanical section.
Each monitoring state can be assigned its own indicator element. Alternatively, in a suitable design at least one indicator element displays at least two of the different monitoring states. The threshold value is upwardly or downwardly exceeded, a normal function and a critical state, and at least one common indicator element is used for monitoring signals obtained from different sensors.
The dependability of monitoring is enhanced because the indicator state showing that a threshold value is upwardly or downwardly exceeded is maintained until an operator resets.
If the threshold values are stored in a fixed value memory of the control device and are changed by keys arranged on the device housing, or via a connecting line from a remote position, or by means of radio, then the threshold values can be made available in a simple manner and can also be changed.
The monitoring options and operating options are increased because the monitoring signals can be transmitted via a connecting line or via radio to a location outside of the switchgear cabinet, and because several switchgear cabinet monitoring arrangements are connected to a net and are linked to a higher monitoring position.
By means of these steps a switchgear cabinet monitoring arrangement is made available, which is not elaborate and is cost-effective.